1. Field
The present invention relates generally to communication encoding and, more particularly, to communication encoding within a bidirectional system.
2. Description of Related Art
There are systems that provide bidirectional communication between multiple devices similar to that depicted in FIG. 1. Such systems usually employ an open drain configuration which allows multiple devices to be connected to the same data line. Thus, multiple devices can drive information onto the single data line. In this arrangement, whenever a device drives a logical low onto the data line, current is consumed at a rate of VSUPPLY/(RPULL-UP+ROPEN DRAIN). Whenever transmitting a logical one, the open drain device is turned off and very little power is used. However, for low power systems, the resulting communication current can exceed the capability of the system if a number of consecutive logic lows are transmitted on the data line.
One attempt to address this excessive current that is used during the transmission of consecutive logic lows involves using unidirectional lines between each of the multiple devices. However, in this solution, the number of lines increases proportional to the number of devices.
Accordingly, there remains a need for a technique that encodes information in a way that reduces the amount of current consumed while retaining the benefits of a bidirectional open drain communication system.